Technical advances in mobile terminals and the desire of consumers to have ubiquitous access to distributed information have fueled the development of the wireless Internet, which consists of a core wired network and various wireless access networks with different topologies and capacities. To ensure continuous and seamless connection within this hybrid network, mobility management protocols are required to bridge the various network entities and mobile terminals.

It is generally accepted that the mobility management infrastructure is split into macro-mobility and micro-mobility management. Macro-mobility deals with large-scale mobility support for mobile terminals roaming between different domains, whereas micro-mobility deals with small-scale mobility support for mobile terminals roaming within a single domain. Several micro-mobility protocols have been proposed. These protocols can be divided into two categories: HSR (host-specific routing) protocols and ABT (agent-based tunneling) protocols. In an HSR protocol, mobility agents maintain host-specific entries to each mobile node for routing. In an ABT protocol, packets delivery is based on tunneling between mobility agents.

We consider both main categories, and conclude that ABT architecture is a more evolutionary and scalable solution than HSR architecture. We therefore investigate ABT protocols in order to improve latency performance in both location management and handoff management. We propose a protocol based on ABT architecture known as

Dynamic Mobility Agents Protocol (DMAP). Our solution differs from most existing protocols, where mobile users are assigned one or more fixed regional mobility agents. In a hierarchical network architecture, DMAP selects and dynamically changes the mobility agent for each user, according to its mobility level and possible roaming range. We also present the results of our analysis to show the optimized performance ofDMAP.